Stop compiler warning about NSURL
MIDI Clock - Shuffling locate code (not actually used yet)
- Subscribe to Session::Locate to detect seeks
- Shuffle Mclk locating computations into a separate private class
Test code removal...
- Send position data from internal position class
- Proper midi beat conversions for all time signatures
- Disable responding to Session::PositionChanged in place
  of Session::Located.
Human readable printing of MIDI Position messages
WIP - Experimenting with an alternative clock generating algo
    - Transport debug output (tracing where transport_frame
      is updated
Revamp clock processing so it uses an internal frame reference.
MidiClockTicker::Position managed by boost::scoped_ptr
Make Session::send_song_position_pointer a no-op
Midi clock housekeeping